An electrochemical fuel cell is a device that converts fuel and an oxidant to electricity, a reaction product, and heat. For example, fuel cells may be adapted to convert hydrogen and oxygen into water and electricity. In such fuel cells, the hydrogen is the fuel, the oxygen is the oxidant, and the water is the reaction product.
A fuel cell stack is one or more fuel cells, including groups of fuel cells, coupled together as a unit. A fuel cell stack may be incorporated into a fuel cell system. A fuel cell system also typically includes a fuel source, such as a supply of fuel and/or a fuel processor. An example of a fuel processor is a steam reformer. The system may also include a battery bank, which stores produced electrical power, and an air source, which delivers oxygen to the fuel cell. There is a need to control fuel cell stacks and other fuel cell system components to regulate the operation of the system, such as to prevent damage to the system and/or to operate the system efficiently in response to applied loads.